This invention relates to methods, compounds and devices for adhering items together and more specifically, to adhesive and removal methods and apparatus for securing and removing secured items such that they are removed through the application of magnetic fields.
Throughout daily life, there are many occasions requiring that two or more items be secured to one another. For example, in the field of dentistry, there are several ways to permanently secure prosthodontics such that they maintain a proper spatial relationship to either part of an existing tooth or a dental implant. A more commonly employed technique involves the use of some form of dental cement placed between the tooth or implant and the prosthodontic device. Dental cement chemistry is a complex science and the actual method of "affixation" varies. In some types of dental cement, the cement flows into surfaces characterized by micro roughness on the items being cemented. These micro rough surfaces hold onto the cement once the cement has set, thus holding the items together.
While these cements allow for a firm bond, removing the cemented prosthodontics can be difficult, time consuming, and uncomfortable for both the patient and the dentist. Additionally, physical forces generated in conventional removal processes can damage the underlying tooth or implant. For this reason many affixed prosthodontic devices are infrequently removed for examination, except when dental problems arise.
In the field of prosthodontics, it has been known to employ magnets for securing items together. However, this use of magnetism has hereto been restricted to applications involving affixation between two prosthodontic devices such as an implant and a crown, bridge, or denture. One problem with prior magnetic affixation, typically using a magnet and a ferromagnetic material to which the magnet holds (or another magnet), is the lack of holding power to prevent relative movement between the affixed components. U.S. Pat. No. 4,693,686 (Sendax) incorporates pairs of magnets with one magnet positioned within an implant and the other magnet positioned within a prosthodontic device. The attractive forces between these magnets secure the prosthodontics. U.S. Pat. No. 4,214,366 (Laban), U.S. Pat. No. 5,788,493 (Tanaka et al), U.S. Pat. No. 5,678,998 (Honkura et al), U.S. Pat. No. 5,611,689 (Stemmann), and U.S. Pat. No. 4,997,372 (Shiner et al) all use variations in design of similar concepts. Other patents such as U.S. Pat. No. 5,636,990 (Stemmann), U.S. Pat. No. 5,254,006 (Yamada), and U.S. Pat. No. 5,013,243 (Tanaka et al) function in similar ways, but use the attractive forces between a single magnet and a ferromagnetic material to secure prosthodontic devices in position.